In accompany with developments in electronic industries, kinds of electronic products generate economic benefits and improve our daily lives. Currently, electronic products are getting shorter, smaller, lighter and thinner. In order to miniaturize the circuit boards of electronic products, the connection line between elements should be shortened. Though straight lines are the shortest, it is impossible to keep all the connection lines simply straight since the considerations of component locations, heat dissipation and signal interference problems. An easier way is to connect the components with straight lines and right-angled lines.
However, traces in right angles cause three effects: capacitor effect, electromagnetic interference and signal reflection. Signal reflection is especially evident when the electronic circuit is applied for high frequency signal transmission. As shown in FIG. 1A, an explanatory view of signal reflection in a right-angled portion, when signal 11 passes through the right-angled portion 10a of a circuit 10, the discontinuous impedance in the circuit 10 causes reflective noise signal 11. The reflective signal interferes the signal transmission and may even cause mistake or malfunction of the integrated circuit.
Conventional circuit layout for a right-angled portion 10a of a circuit 10 is arranged as shown in FIGS. 1B to 1D. In FIG. 1B, one side of the right-angled portion 10a is slant, while the other side is rectangular. Therefore, the slant portion in 45 degrees turns the signal path 90 degrees to reduce signal reflection. However, it relatively increases the path length and area of the circuit 10. In FIG. 1C, both sides of the right-angled portion are slants of 45 degrees to turn the signal path 90 degrees. The reflection reduction of FIG. 1C is better than that of FIG. 1B. However, it still increases the path length and area of the circuit 10. In FIG. 1D, both sides of the turning portion 10a are arcs to turn the signal path 90 degrees. The performance of reflection reduction is the best. However, the fabrication of the line is much difficult.
Therefore, to provide a trace method that can prevent signal reflection interference and reduce printed circuit board dimensions is a demand of manufacturers and technicians.